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224                     Regulator Valve Spindle.

along the top, as at H Then, in position H, scribe and square
the centre d, measuring the distance c from a straight edge at b.
Strike the circle for the hole, drill this tapping size, and tap to
suit the Bracket No. II. To ensure rigidity, the bracket should
have been screwed rather f full/ and be now taken down with
stock and dies until a perfect fit in d. The port is to be marked
off, as at j, with square and straight edge, and measurements from
the square flange, and the edges are then to be chipped and filed
by hand, an operation involving some trouble.

The Cover is to be planed and drilled. Find the centre of
the gland seating as at B, Fig. 237, and mark also the centres at
each end; then draw a line across. Set the cover level on the
marking-table, as at c, and squaring up the centre d, scribe the
thickness of the plate, and mark its width. Set central, on the
planing machine, in a machine vice, or its equivalent, as at D and
E. Level the cover to the scribed lines, and plane the side sur-
faces, a a and bl>, as well as the edges. Remove, and square
across for the adjacent sides, as shewn at F, using the gland seat-
ing as a guide. Then set in the planing machine, and tool the
edges; finish the surfaces e e to the same level as a and b. Now
reverse the plate, and, setting level in the machine vice, as at G,
scribe the gland surface to measure correctly from the surface a b e,
and plane. The cover is next to be marked for drilling, which is
shewn at H, and the holes gg drilled to clearance size, h to
tapping size, while j must first be drilled for the smaller diameter,
and the stuffing-box afterwards taken put with a pin drill specially
cut, as at j.

The Gland is first drilled in the lathe (B, Fig. 238), which
may be done more truly by blocking up the hole with wood
through its entire length, and letting the drill take this out. The
front may be surfaced at the same time. Next place upon a
mandrel as at c, and turn down to dimensions. Remove, span
the centre, and mark off the gland face as at D ; then drill the
holes (clearance), and finish off the edge with dead smooth file
and fine emery. The cover holes are lastly to be marked off on
the box by tracing through from the cover, then drilled and
tapped.                                                                       *

IX. Valve Spindles: Main and Expansion (Fig. 239),